Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to the prior art by inclusion in this section.
Modern motor vehicles often include one or more driver information and driver assistance systems (hereinafter referred to as in-vehicle information systems) that provide a wide variety of information and entertainment options to occupants in the vehicle. Common services that are provided by the in-vehicle information systems include, but are not limited to, vehicle state and diagnostic information, mapping and navigation applications, hands-free telephony, radio and music playback, and traffic condition alerts. In-vehicle information systems often include multiple input and output devices. For example, traditional buttons and control knobs that are used to operate radios and audio systems are commonly used in vehicle information systems. More recent forms of vehicle input include touchscreen input devices that combine input and display into a single screen, as well as voice-activated functions where the in-vehicle information system responds to voice commands. Examples of output systems include mechanical instrument gauges, output display panels, such as liquid crystal display (LCD) panels, and audio output devices that produce synthesized speech.
Three-dimensional (3D) graphics methods have been widely used in different driver assistance and driver information applications. One typical example is navigation systems based on 3D maps. Compared with traditional two-dimensional (2D) maps, 3D maps are considered to be more helpful for easy driver orientation and fast location recognition. For example, photorealistic 3D mapping and navigation services are provided by multiple online and offline services including services offered by Apple, Google, and Nokia. Modern 3D graphics can produce a wide range of highly realistic graphical effects. In the context of 3D mapping and navigation applications, a graphics display system can generate landmarks such as geographic features, streets, buildings, and other landmarks in great detail. Furthermore, some 3D mapping systems can apply graphical effects that depict the weather and lighting conditions in the 3D virtual environment that correspond to the actual weather conditions in the real geographic region that is reproduced in the mapping application. For example, 3D graphics systems can produce graphical renderings of clouds based on the current weather conditions in a geographic region.
While modern 3D graphics hardware and software is capable of reproducing a wide range of graphics, the generation of graphical effects such as clouds typically requires substantial hardware execution resources to produce the graphical effects with a reasonable rendering speed for use a 3D mapping application. Modern processing devices including graphics processing units (GPUs) that can perform complex graphical rendering of realistic three-dimensional clouds exist, but many hardware platforms including the graphics systems that are integrated into motor vehicles and those of inexpensive mobile electronic devices may lack the necessary hardware to produce realistic graphical depictions of clouds. Furthermore, even some mobile electronic devices that now include increasingly powerful graphics hardware may consume an undesirably large amount of electrical power to produce the graphics, which often results in a drained battery that can be counterproductive to the use of a mapping application when traveling. Consequently, improvements methods and systems that render of clouds in three-dimensional virtual environments to produce a graphical rendering of the cloud cover in a geographic region in a computationally efficient manner would be beneficial.